Multiple joint tandem suspension with torque springs

ABSTRACT

A tandem vehicle suspension having a compensator member pivotally supported on a transverse trunnion depending from a vehicle chassis, independent forwardly and rearwardly extending torque springs pivotally connected to the compensator at one end and to the forward and rearward axles, respectively, at their other ends, and bearing means between the compensator and torque springs, the respective pivotal connections and bearing means creating greater reactive forces and better load distribution between the two axles.

United States Patent 1 Raidel Aug. 7, 1973 MULTIPLE JOINT TANDEMSUSPENSION WITH TORQUE SPRINGS Inventor:

Assignee:

Filed:

John E. Raidel, Springfield, Mo.

Ridewell Corporation, Springfield,

Nov. 16, 1971 US. Cl. 280/l04.5 A, 280/80 B, 267/56 Int. Cl. 860g 5/04Field of Search 280/lO4.5 A, l04.5 R,

References Cited UNITED STATES PATENTS I l 2/1940 lO/I953 l()/ l 969Larison 280/l04.5 A Nabors...; 280/l04.5 R Raidcl 280/l04.5 R Raidel267/56 Primary ExaminerPhilip Goodman Assistant Examiner-John A. CarrollAttorney-Rogers, Ezell, Eilers & Robbins [57] ABSTRACT A tandem vehiclesuspension having a compensator member pivotally supported on atransverse trunnion depending from a vehicle chassis, independentforwardly and rearwardly extending torque springs pivotally connected tothe compensator at one end and to the forward and rearward axles,respectively, at their other ends, and bearing means between thecompensator and torque springs, the respective pivotal connec' tions andbearing means creating greater reactive forces and better loaddistribution between the two axles. A

9 Claims, 7 Drawing Figures PATENIED 3.751 063 sum 1 OF 2 INVENTOR. JOHNE. RA/DEL,

MULTIPLE JOINT TANDEM SUSPENSION WITH TORQUE SPRINGS SUMMARY OF THEINVENTION This invention relates to a tandem vehicle suspension assemblyand particularly to an independent two-axle suspension with multiplejoint and flexing torque springs. On each side of the vehicle body apedestal is suspended from the chassis. A trunnion shaft is mountedbetween the pedestals, and a compensator in the form of an inverted'U-shaped channel member is pivotally connected by a resilient bushingto each end of the trunnion shaft. Forwardly and rearwardly extendingtorque springs are pivotally connected by resilient bushings to thechannel member and by clamp assemblies to the respective forward andrearward axles. Bearing means are mounted between the torque springs andthe top of the channel member against which the torque springs bear inthe loaded condition. The compensator oscillates independently about itstrunnion pivot and equalizes the load distribution among the axles. Thetorque springs are pivoted to the compensator and flexed against thebearing means, providing the axles with independent axle movement.

The bushing which connects the compensator to the trunnion shaft isabove and between the bushings which connect the torque springs to thecompensator. Therefore, when the truck brakes are applied, the resultingmoments and forces against the compensator are in a downward, ratherthan an upward, direction and are of sufficient magnitude to eliminatebouncing.

Also, since the connections of the torque beams and the compensator areby resilient bushings, limited lateral swinging of the torque springscan take place when the vehicle makes a turn. The wheels automaticallytrack with the turn, thereby reducing or eliminating skidding, andproviding a safer, more certain control of the vehicle.

DESCRIPTION 01- THE DRAWINGS FIG. 5 is a view in section taken along theline 5--5 of FIG. 1; I

FIG. 6 is a view in section taken along the line 6-6 of FIG. 2; and

FIG. 7 is a view similar to FIG. 4 but showing a rear end elevation viewof the entire pedestal assembly for mounting the suspension to thevehicle chassis.

A DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT:

The tandem suspension assembly 20 cemprises a pedestal 21' fastened atits top by any suitable means such as welding or bolting to a vehiclechassis 23. The pedestal 21 has a suitable bearing surface 24 thatenables it to be rigidly secured to the vehicle chassis 23, and hassuitable stiffening flanges 25 and 26, and cross braces 27 which extendto an identical pedestal at the other side of the vehicle chassis. Atits lower end. the

pedestal 21 has a flat lower side 28 against which the upper plate 30 ofa cast bracket 31 is mounted. The cast bracket 31 is fastened to thepedestal 21 by a plurality of bolts 34. v

The cast bracket 31 has a disk portion 32 and rests upon and is weldedto a trunnion shaft 33 that extends the width of the vehicle body. Asshown in FIG. 4, the trunnion shaft 33 is hollow and has an internal endplate 35 welded in place.

A bushing assembly 37 is mounted on the trunnion shaft 33 outwardly ofthe cast bracket 31. The disk portion 32 has an annular recess 39. Atrunnion cap 40 is mounted onto the end of the trunnion shaft 33 by abolt 41 that extends through the trunnion cap 40 and the end plate 35.The section 42 of that bolt 41 that is journaled in the end plate'35 iseccentric relative to the shank of the bolt. The trunnion cap 40,has aradially outwardly extending flange'43 with an annular recess 44. Arubber bushing 45 is mounted on and adhered to the trunnion shaft 33between the recesses 39 and 44 of the disk portion '32 and end cap 40. Ametal sleeve or housing 46 is adhered to and surrounds the rubberbushing 45, and is positioned between the disk portion 32- and theannular flange 43 of the end cap 40, restricting' axial movementrelative to the trunnion shaft 33.

A-compensator 49 comprises-an inverted U-shaped channel member having atop 50 and sides 51 and'52. The compensator 49 is mounted on the sleeve46 with the sleeve 46 extending throughop'enin'gs 53 and 54 in the sides51 and 52. A spacer bracket 55 is mounted such as by welding between thesides 51 and52 of the compensator 49 beneath the bushing assembly37 andincludesa bottom plate 56, verticalplate 57, and triangular brace plates58 and 59 between the bottom plate 56 and vertical plate 57. Areenforcing rib 60 is located on the outer surface near the bottom ofeach side 51 and 52. I

A pair of torque springs 62 and 63', preferably having multiple leaflayers, are pivotally connected to the channel member 49 by bushingassemblies 64 and 65. The axes of the bushing assemblies 64 and'6'5 arebelow the axis of the bushing assembly 37, preferably by at least twoinches.

As shown in FIG. 6, each bushing assembly 64 and I55 includes a capscrew or bolt having a head 71 and a shank 72 with a cam member 73welded to the shank 72 and projecting to one side. The cammember 73 actsas an eccentric. An arrow (not shown) is drawn or stamped on the face ofthe bolt head 71 and points to the central highrise of the cam eccentric73. The shank 72 of the bolt 70' extends'througha hole'77 in a plate 79positioned within a frame 803 The frame 80 is welded tothe side 52 ofthe compensator 49 and'pr'events the plate 79 from rotating; The; shank72 extends on through a hole in the side 52, a hole 87 in the side 51 ofthe compensator 49, anda hole 8 9 in a plate 91, welded against the side51. A lock washer and'anut 97 are usedtc tighten the bolt 70 in place. Ametal sleeve 99 surrounds the shank 72am! the cam eccentric73 of thebolt 70, and a rubberbushin'g 101 surrounds and is bcndedte the sleeve99. There are washers I03 and 104'at each endof the rubber bushing 101.

Each of the torque springs 62a'nd 63 comprises a'plurality of springmembers icrm'ed in layers, the torque spring 62 having an upperspring-member 110. a middle spring member 111. and a lower spring member112, and the torque spring 63 having an upper spring mam her 113, amiddle spring member 114, and a lower spring member 115. Although thetorque springs are described having three spring members, the number ofmembers would depend on the desired capacity rating. An end 117 of thelower spring member 112 is wound around the rubber bushing 101 of thebushing assembly 64 and an end 119 of the middle spring member 111 ispartially wound about the end 117 of the lower spring member 112.Likewise an end 121 of the lower spring member 115 is wound about therubber bushing 101 of the bushing assembly 65, and an end 123 of themiddle spring member 114 is partially wound about the end 121 of thespring member 115. The upper spring members 110 and 113 do not curvearound the bushing assemblies 64 and 65 but terminate at a pointapproximately directly above the bolts 70 of the bushing assemblies 64and 65. If more spring members are used, they likewise would beprogressively shortened.

The torque springs 62 and 63 extend forwardly and rearwardly,respectively, to a pair of axle mount assemblies 130 and 131. As shownin FIGS. 2, 3, and 5, each axle mount assembly 130 and 131 comprises abracket 133 having an upper concave seat 135 and sides 136 and 137.Bottom plates 139 and 140 are wider than the bracket 133 and includeholes 141 near their side edges outside the bracket 133. A support plate142 resting on the plates 139 and 140 has a pin 143 (FIG. that extendsvertically upward within the bracket 133 and through aligned holes in,the spring members near the outer ends of eachtorque spring 62 and 63.The lower end of the pin 143 extends into a recess 144 of the plate 139.The pins 143 hold the springmembers of each torque spring in alignmentat their outer ends so that any relative movement between the springmembers due to flexing of the torque springs 62 and 63 occurs at theends mounted to the bushings 64 and 65. The front axle 150 of thevehicle is welded in the concave seat 135 of the axle mounting assembly130, and the rear axle 152 of the vehicle is welded in the concave seat135 of the axle mounting assembly 131. Each axle mounting assembly 130and 131 includes a pair of U- bolt and nut assemblies 153 and 154 withthe U-bolts extending over the axles and down through the holes 141 inthe lower plate 139 to firmly secure the axles to the torque springs.

A front wear plate 155 is mounted between the top 50 near the front ofthe compensator 49 and the top of the forward torque spring 62. A rearwear plate 156 is mounted between the top 50 near the rear of thecompensator 49 and the top of the rearwardly extending torque spring 63.When the suspension assembly 20 is in its loaded condition as shown inFIG. 2, the upper surfaces of the torque springs 62 and 63 rest againstthe wear plates 155 and 156, respectively.

ln place of the wear plates 155 and 156, the sleeve bearings of FIG. 5of U. S. Pat. application serial No. 866,203, filed Oct. 14, 1969, orother suitable bearing means could be used.-

A pair of wear sleeves 160 and 161 are mounted in any suitable mannerbetween the sides 51 and 52 of the compensator 49 with the wear sleeve160 mounted near the front of the compensator 49 just under and out ofcontact with the lower surface of the torque spring 62, and the wearsleeve 161 mounted near the rear of the compensator 49 just under andout of contact with the lower surface of the torque spring 63 when thesuspension assembly is in its loaded condition. When the suspensionassembly is unloaded, that is, when the chassis is lifted such that thewheels are off the ground, the torque springs 62 and 63 drop so as torest on the wear sleeves 160 and 161, respectively. This condition couldalso occur where rough road conditions cause the chassis to moveupwardly such that the wheels leave the ground.

OPERATION The suspension assembly 20 is, of course, duplicated on bothsides of the truck chassis 23 with the trunnion shaft 33 extending thewidth of the truck and being common for both suspension assemblies, andwith the axles and 152, as well as the chassis 23 being similarlyconnected to both assemblies.

The functions of the suspension assemblies 20 are to resiliently supportvarying total loads carried by the vehicle body above the vehiclechassis 23, to respond to uneven distribution of loads either forwardlyor rearwardly of the vehicle chassis, compensating for such unevendistribution, and distributing such load substantially equal to bothaxles 150 and 152, and to react to I and dampen individual shock forcesapplied to either axle 150 or 152 by rough or uneven spots in theroadway.

In addition as has been said, the useof the resilient bushings 64 and 65permit limited lateral turning of the torque springs 62 and 63 relativeto the compensator 49. Also the resilient bushing 37 permits limitedlateral turning of the compensator 49 relative to the trunnion shaft 34.As a result, when the vehicle turnsa comer, the wheels carried by theaxles 150 and 152 can and do track with the turn. This eliminatesskidding of the tires on the roadway and gives the driver bettercontrol.

Assume first that an uneven distribution of load is carried by thevehicle chassis 23. With an uneven load, there is virtually no tendencyof the vehicle chassis 23 to swing downwardly at either its forward orrearward end to rock the pedestal 21 and apply a torsion load to thebushing assembly 37. The applied load is vertical, and the vertical loadis transmitted through the pedestal, the trunnion shaft 33, and thebushing assembly 37 into a vertical downward force on the compensator49. As the compensator 49 moves downwardly under the vertical load, thewear plates and 156 apply pressure to the upper surfaces of the torquesprings 62 and 63 and, at the same time, move the bushing assemblies 64and 65 downwardly. Since the axles 150 and 152 are substantiallyimmovable because they rest upon the immovable roadway, downwardmovement of the compensator 49 tends to produce clockwise rotation, ofthe torquespring 62 about the bushing assembly 64 and counterclockwiserotation of the torque spring 63 about the bushing assembly 65, asviewed in FIG. 2. This combined action produces upward flexing of thetorque springs 62 and 63 at the wear plates 155 and 156 to absorb thevariations in the load carried by the truck chassis.

There is a similar action when one of the axles 150 or 152 is bouncedupwardly by an unevenness in the roadway. For example, if the axle 150moves upwardly, it tends to swing the torque spring 62 in a clockwisedirection causing it to flex upwardly all the more against the wearplate 155. The wear plate 155 reacts with the force tending to rotatethe compensator 49 in a clockwisedirection and thereby tending to rotatethe pedestal 21 and the vehicle chassis 23 in a clockwise direction.However, as soon as the compensator starts to rotate in a clockwisedirection, the wear plate 156 bears all the more against the uppersurface of the torque spring 63 causing it to flex upwardly all themore. The resulting increased flexing of the torque spring 63 is inreaction to the increased flexing of the torque spring 62 and tends toequalize the load on the axles 150 and 152 and maintain the vehiclechassis 23 level.

A particular feature of this invention is the use of flexible springs asthe torque springs 62 and 63. These flexible springs provide anunusually comfortable ride and act in combination with the compensator,relative arrangement of the bushings 37, 64, and 65, and the otherfeatures of the suspension to prevent axle or brake hop and provideequal distribution of the load on the axles, independent axle movement,and excellent stability.

Other features of this invention are the use of eccentric bolts in thebushings 37, 64, and 65. Since the bolt 41 in the bushing 37 thatsupports the compensator 49 has an eccentric 42, the bolt can beloosened and rotated to balance the compensator. Likewise the eccentricbolts70 in the bushings 64 and 65 used to mount the torque springs 62and 63 to the compensator 49 can be loosened and rotated to providepositive axle alignment. For example, in this embodiment the rotation ofeach bolt 70 moves the axle as much as one-half inch between inward andoutward positions. Since each side of the chassis has two eccentricbolts 70, one in each of the bushings 64 and 65, a total one inchadjustment is available on each side. k

Various changes and modifications maybe made in this invention, as willbe' readily apparent to those skilled in the art. Such changes andmodifcations are within the scope and teachingof this invention asdefined by the claims appended hereto.

-What is claimed is: v i

l. Avehicle suspension assembly comprising a pedestal adapted to besuspended from a vehicle chassis between two axles of the vehicle, acompensator, means for connecting the compensator to the pedestal foroscillating movement of the compensator relative to the pedestal aboutan axis parallel to the axles of the vehicle, a forward flexible torquespring, means for pivotally connecting one end of the forward spring tothe compensator, means for connecting the other end of the forwardspring to-the front one of the two vehicle axles, a rearward flexibletorque spring, means for pivotally connecting one end of the rearwardspring to the compensator, means for connecting the other end of therearward spring to the rear one of the two vehicle axles, the torquesprings supporting the entire load on the axles, and upper bearing meansmounted to the compensator above the upper surface of each torque springbetween its axle and pivotal connection means which bears against thetop surface of the torque spring when the suspension assembly is underload, the torque springs acting as flexible cantilevers to support thechassis on the axles.

2. The vehicle suspension assembly of claim 1 including lower bearingmeans mounted in the compensator beneath the lower surfaces of thetorque springs such that with the assembly in its unloaded condition,the bottom surfaces of the torque springs rest on the lower bearingmeans.

3. The vehicle suspension assembly of claim 1 wherein the upper bearingmeans are wear plates.

4. The vehicle suspension assembly of claim 1 wherein the upper bearingmeans are bearing sleeves.

5. The vehicle suspension assembly of claim 1 wherein the connectingmeans between the compensator and the pedestal comprises a rotaryeccentric-for changing the oscillatory axis of the compensator relativeto the pedestal.

.6. The' vehicle suspension assembly of claim 1 wherein the flexibletorque springs are multilayered leafsprings. a

- 7. The vehicle suspension assembly of claim 1 wherein the. connectingmeans between the forward torque spring and the compensatorand theconnecting a means between the'r'earward torque spring and thecompensator comprise rotary eccentrics for'changing the pivotal axes ofthe forward and rearward torque springs relative to the compensator toprovide means for aligning the axles. 5

8. The vehicle suspension assembly of claim 1 wherein the connectingmeans between the forward torque spring and the compensator and theconnecting means between the rearward torque spring and the compensatorcomprise rubber bushing means, the rear end of the forward torque springbeing journaled about its connecting bushing and the forward end oftherearward torque spring being journaled about its connect ing bushing.

9. The vehicle suspension assembly of claim 1 wherein the pivotalconnections of the flexible torque springs are below the connectingmeans between the compensator and the pedestal.

k l 4 t! l

1. A vehicle suspension assembly comprising a pedestal adapted to be suspended from a vehicle chassis between two axles of the vehicle, a compensator, means for connecting the compensator to the pedestal for oscillating movement of the compensator relative to the pedestal about an axis parallel to the axles of the vehicle, a forward flexible torque spring, means for pivotally connecting one end of the forward spring to the compensator, means for connecting the other end of the forward spring to the front one of the two vehicle axles, a rearward flexible torque spring, means for pivotally connecting one end of the rearward spring to the compensator, means for connecting the other end of the rearward spring to the rear one of the two vehicle axles, the torque springs supporting the entire load on the axles, and upper bearing means mounted to the compensator above the upper surface of each torque spring between its axle and pivotal connection means which bears against the top surface of the torque spring when the suspension assembly is under load, the torque springs acting as flexible cantilevers to support the chassis on the axles.
 2. The vehicle suspension assembly of claim 1 including lower bearing means mounted in the compensator beneath the lower surfaces of the torque springs such that with the assembly in its unloaded condition, the bottom surfaces of the torque springs rest on the lower bearing means.
 3. The vehicle suspension assembly of claim 1 wherein the upper bearing means are wear plates.
 4. The vehicle suspension assembly of claim 1 wherein the upper bearing means are bearing sleeves.
 5. The vehicle suspension assembly of claim 1 wherein the connecting means between the compensator and the pedestal comprises a rotary eccentric for changing the oscillatory axis of the compensator relative to the pedestal.
 6. The vehicle suspension assembly of claim 1 wherein the flexible torque springs are multilayered leaf springs.
 7. The vehicle suspension assembly of claim 1 wherein the connecting means between the forward torque spring and the compensator and the connecting means between the rearward torque spring and the compensator comprise rotary eccentrics for changing the pivotal axes of the forward and rearward torque springs relative to the compensator to provide means for aligning the axles.
 8. The vehicle suspension assembly of claim 1 wherein the connecting means between the forward torque spring and the compensator and the connecting means between the rearward torque spring and the compensator comprise rubber bushing means, the rear end of the forward torque spring being journaled about its connecting bushing and the forward end of the rearward torque spring being journaled about its connecting bushing.
 9. The vehicle suspension assembly of claim 1 wherein the pivotal connections of the flexible torque springs are below the connecting means between the compensator and the pedestal. 